Thermo-electro-responsive device



I Mmh24, 1931. H. E. RUFF I 1,797,370

THERMO- ELECTRO-RESPONS IVE DEVICE Original Filed May 20, 1926 2Sheets-Sheet l iii lifi

March 24, 1931. H4 1:. RUFF 1,797,370

THERMO-ELECTRO-RESPONSIVE DEVI CE Original Filed May 20, 1926 '2Sheets-Sheet 2 nvcnrct A EEBa ET E. EUPP Chrome Patented Mar. 24, 1931UNITED STATES PATENT OFFICE HERBER'F E. RUPP, OF MANSFIELD, OHIO,ASSIGNOR TO THE OHIO BRASS COMPANY, OF MANSFIELD, OHIO, A CORPORATION OFNEW JERSEY THERMO-ELECTRO-RESPONSIVE DEVICE Original application filedKay 20, 1926, Serial No. 110,411. Divided and this application filedDecember My invention relates to a thermo-responsive device forcontrolling the flow of currents and can be used as a switch or tocontrol other mechanism. I

I have shown the device as applied to the operation of a rotatableswitch, but for the sake of simplicity, I switch in detail, as thedevice can be used to controlthe operation of a rotary or other type ofswitch, as for instance, the operation of the rotary switch as shown indetail in copending application, Serial No. 102,653, filed April 17,1926, in the name of Edgar D. Moore, with which I' am familiar.

This application constitutes a division of my co-pending application,Serial No. 110,- 411, filed May 20, 1926, for a thermo-electroresponsivedevice.

I have devised a thermo-responsive device which can be used alone as aswitch or in combination with electrically controlled mechanism, whichin turn my invention will control, and which is new and novel and theadjustment of which is not affected by changes in temperature of thesurrounding atmosphere.

One of the objects of my invention is to provide a mechanism which canbe connected to a circuit, and when the current flowing in the circuitsuddenly exceeds a predetermined amount the mechanism will operate toopen the switch.

Another object of my invention is to provide in the mechanism athermo-responsive device which acts as a switch to control the operationof the mechanism when the current flowing in the circuits exceeds apredetermined amount for a predetermined time.

Another object is to provide a thermo-responsive device comprising aplurality of thermal elements in which all the thermal elements areaffected by a common means and one of the elements is affected by otherindependent means.

A further object is to provide a means of protecting an electrictranslating device from a dangerous rise in temperature.

Another object of my invention is to provide means for rendering thethermo-responhave not shown the 1926. Serial No. 154,443.

with a rotary switch, as set forth above, for I controlling the circuitsleading to electrically operated translating devices such as motors,

lights, etc., it provides a means of protecting the translating devicefrom sudden overloads and also from loads sufficiently high to cause adangerous heating of the translating device when not sufliciently highto cause the overload to operate. In other words, it

will permit the translating device to carry its maximum safe load.

I have shown certain parts of my invention in the attached drawing inschematic form, as the construction is simple and well known to thoseskilled in the art, and to make the disclosure in other form than shown,it is believed would merely complicate the understanding of theinvention.

My invention resides in the new and novel construction, combination andrelation of the various parts herein described and shown in theaccompanying drawing.

- In the drawings:

.Fig. 1 is a plan view, partially schematic.

Fig. 2 is an end view of Fig. 1.

Figure 3 is a right-hand side view of Fig. 1.

Fig. 4 isa left-hand view of Fig. 1.

Fig. 5 is a detail of the thermostatic control with a portion brokenaway.

Fig. 6 is a sectional view on the line 66 of Fig. 5 to show anadjustable member on the thermostatic control.

Fig. 7 shows one of the elements of the thermostatic control.

Fig. 8 shows my device as applied to a rotary switch, referred tobefore, and to a translating device.

Fig. 9 shows a modification of the relay construction shown in Fig. 1.

In the preferred construction of my relay, I employ a base member 1,preferably of insulating material. Mounted upon the base 1 is amagnet M,which does not differ in principle from other well known magnets, butwhich comprises a core 2, end members 3 and; secured to the core member2 by means of screws and secured to the base 1 by means of the screws 5.The end members 3, and 4 may both be made of iron, but the end member 3may be made of other material. The armature 6, w hich is also of ironand movably secured to the end member 3 by means of the spring 7, itattracted by the end member 4. The base 1 has mounted thereon theterminal posts 8, 9, 10 and-11.

The core 2 is provided with a coil 12 having one terminal connected tothe post 8 by the conductor 13 which is preferably concealed within thebase 1. The other end of the coil 12 is connected to the post 10 bymeans of the conductor 14, also preferably enclosed within the base. Thecoil 12, it will be noted, isconnected in series in the circuit betweenthe posts 8 and 10, therefore, all current flowing through the circuitconnecting the posts 8 and 10 will flow through the coil 12. This coil Iprefer to construct of copper and of reasonably low resistance in orderto cut down resistance losses, as it forms a part of the main circuitconducting current whenever the device is in use.

The core 2 is provided at each end with insulating discs 15 andsurrounding the core is also insulating material to maintaininsulationbctween the coil 12 and the adjacent metal pa rts. Thisconstruction is well known to those skilled in the art.

Mounted on the base 1 is a thermostatic responsive device T whichcomprises an insulating member 16 secured to metallic standards 17 and17 by means of the screws 18 and 18'. Mounted on the insulating member16 is a bi-metal thermostatic element 19 composed of two dissimilarmetals whose temperature co-eflicients are different. This bimetalelement is well known in the trade. The element 19 is secured to theinsulating member 16 by means of the screw 20 and at its distant end isa contact element 21 secured thereto which may be of metal, butpreferably of carbon.

Also mounted on the insulating member 16, but spaced from the element19, is a U-shaped bi-metal thermostatic element 22 (see Fig. 7).

This element is provided with contacts 23 and 23, which are mechanicallyand electrically connected to the standards 17 and 17 respectively, bybeing interposed between such standards and the insulating member 16 andheld in position by the screws 18 and 18. At the distant end of theelement 22 is a contact member 24 adapted to engage with the contactmember 21.

The contact 23 of the element 22 is connected to the post 9 by theconductor-25. The contact 23 is connected to the post 11 by means of theconductor 26. From this it will be seen that the U-shaped bi-metalthermostatic element is connected in series with the circuit connectingthe posts 9 and 11 and,

- therefore, the current flowing through the which flows through thecoil 12 will also flow through the ment 22.

The magnet core 2 is provided with an auxiliary winding 27 which has oneterminal connected to the conductor 14 through the U-shaped thermostaticeleconductor 28 and the other terminal being connected to thethermostatic element 19 through the conductor 29 and the screw 20. Itwill be noted that under normal conditions with the contacts 21 and 24separated that no current would flow through the coil 27, but should thecontacts 21 and 24 be brought into engagement then the coil 27 will beconnected between two main circuits connecting the posts 8--10 and 9-11.It will also be noted that when the contacts 21 and 24 are connectedtogether that the two coils 12 and 27 will be in series and connectedacross the opposite circuits. In other words, the main circuits will beconnected together through the coils 12 and 27 in series. For thisreason I prefer to construct the coil 27 of a high resistance materialsuch as iron, German silver, nichrome, etc., thereby introducingsuificient resistance to prevent an unnecessary flow of current betweenthe mains, but stillaccomplish the purpose of the device.

One of the objects of my invention is to provide a device which iscontrolled by temperature changes based upon the current flowing throughthe device and the time that such current flows, therefore, I find itnecessary to provide means of preventing the thermostatic elements fromcontacting under other conditions than those intended and which combinedcurrent and time I will term a sustained current and may be made up ofvarying current and time values, i. e., the greater the current the lessthe time, I find that if only a single thermostatic element is used thatthis element is affected by changes in the surrounding temperature, orwhat might be termed the room temperature, such that if the thermostaticelement should be set to operate under a given room temperature and agiven current after flowing a length of time that this setting wouldvaryshould the room temperature vary. For this reason I employ the twothermostatic elements 19 and 22 so related to each other that the spacebetween the contacts 21 and 24 will remain substantially constantregardless of the changes in the room temperature, as this temperaturewould aflect both elements 19 and 22 alike and, therefore, the spacebetween the contacts 21 and 24 would remain constant or practically so.With the construction shown, in which one the element 22.

element 19 is entire and the other element 22 is U-shaped, I find thatfor all practical purposes such construction maintains the separation ofthe contacts 21 and 24 practically constant providing the elements areof uniform thickness. If it is desired to secure more accurateconditions then the element 19 may be made U-shaped similar to theelement 22.

One function of the thermo-responsive device T is to protect thetranslating device from a too great temperature rise, and as the devicemay be used with different classes of translating devices which willpermit of different temperature raises, I provide means of varying thethermo characteristic of the thermo-responsive device, and I do this bymounting upon the thermo element 22 a rider 30 which is movable upon theelement 22 and will increase or decrease the length of the element 22through which the current can traverse thereby increasing or decreasingthe length of the element 22 is subjected to the heating action of thecurrent. With a given current the movement of the free end of: theelement 22 will be greater or less, depending upon whether the rider 30is closer to the free end or to the fixed end of Therefore, by means ofthe rider 30 I am able to adjust the thermo-responsive device so that itwill operate when the temperature of the translating device X hasreached a predetermined degree or close thereto.

The armature 6 can be made to operate under different conditions byvarying the size or tension of the spring 7. I

In Fig. 8 I have shown a rotary switch S controlled by the operation ofthe armature 6, and this switch will control the opening and closing ofthe main line circuit leading to the contacts 8 and 9. In Fig. 8 theswitch S is shown in its open position. When mydevice is combined with aswitch S and a translating device X, as for instance, a motor, the coil12 will be energized with a normal flow of current insufiicient tooperate the armature 6 and also insufiicient to operate the armature 6under normal starting conditions, but if while running the load on themotor X should be increased suddenly to an abnormal amount then theenergization of the coil 12 would be suflicient to immediately attractthe armature 6 and the switch S would be released to open the circuitfrom the source of supply.

Also, if the translating device X should be operated under a steadyoverload suflicient to endanger the same, but such overload current isnot sufiicient tooperate the armature 6, then after such overloadcontinues for a predetermined time, thereby heating the translatingdevice up to a predetermined amount, then under such operation, when thebeen reached predetermined temperature has e thermo-responsive deuponthe motor, t

which vice would operate, due to the sustained current, to close itscircuit thereby connecting the free end of the coil 27 to the circuit25, and this amounts to throwing the auxiliary coil 27 in series withthe coil 12 and the two across the two sides of the circuit from thesource of power, and current will flow therethrough, directly increasingthe energization of the core 2 by the ampere turns of coil 27, and atthe same time the current through the coil12 will be increased by theamount flowing through the coil 27 thereby further increasing theenergization of the core 2, and which will be sufiicient to cause thearmature 6 to be attracted thereby releasing the spring held switch S toopen the circuits from the source of power.

From this it will be seen that I have a device for protecting the motoragainst a sudden overload of a predetermined amount, or to protect themotor at a lower overload after such overload has raised the temperatureto a predetermined amount.

The switch may consist of a rotatable insulating disc 40 and which isheld under spring tension when in its closed position and biased toopen, as is usual with snap switches. The disc 40 is r'otatably mountedon the stem 41; as is also a lever of insulating material 42, which isfree to rotate relative to the disc 40., The lever 42 is provided with ahandle 43 by means of which the lever 42 is operated. The disc is alsoprovided with four reciprocating contact members 44, 44, 45 and 45connected together by the spring members 46 and 47 which are held to thedisc 40 by the screws 48. These reciprocating contacts are adapted toengage with contacts 4949 and 50-50, which are secured in the base 1.The contact 49 is connected to the post 51 bythe conductor 52 and thecontact 49' is connected to the post 8 by means of the conductor 53,while the contact 50 is connected to the post 54 by the conductor 55 andthe contact 50' is connected to the post 9 by means of the conductor 56.

The armature 6 is provided with a catch 57 which engages with the stop58 when the disc 40 is rotated to its closed position and holds the discin such position thereby closing the circuits from 49 to 49' and from 50to 50.

To close the switch the handle-43 is rotated in a clockwise directionwhich moves the lever 42 into engagement with the projecting contact 45thereafter causing a rotation of the member 40, and this rotation iscontinued until the catch 57 engages with the catch 58. The lower end ofthe lever 42 will now be to the left of catch57.

If it is desired to open the switch by hand the lever 42 is rotated inan anti-clockwise direction through the medium of the handle 43, and theright-hand side of the lower end of the armature contact as shown at athe lever 42 being beveled will engage with the catch 57 therebydepressing the armature 6 and permitting the disc 40 to rotate to anopen position.

As stated at the beginning of this specification, the armature can beemployed to act as a switch in itself, if so desired, in order tooperate or electrically control distant apparatus, and this can bebrought about by securing a vcontact a to the base member of suchconstruction, as is well known to those skilled inthe art, and whichwill engage with 6 if it is desired to operate with. a normally closedcircuit or employ a if it is desired to operate on an open circuit. Ineither case, a conductor would be led from the armature 6 and from thecontact a or a" to such device as is to be controlled by the mechanismshown in It will be noted that when the thermoresponsive element closesthat the twocoils rurrent.

The coil 27 could be made in the form of a resistance R separate fromthe core 2, in which case it would not add to the turns of the core 2,but would still be in series with the coil 12 and this construction isperfectly feasible by properly proportioning the resistance of the saidcoil and the ampere turns of the coil 12 so that sufficient energizationof the core 2 will be secured. o

By connecting the coil 27 as I have shown it permits a smaller number ofturns in the two coils, therefore reducing the size of the device.

There are a number of modifications in my invention which will suggestthemselves to those skilled in the art, therefore, I do not wish to belimited other than by my claims.

0 aim:

1. A circuit closing device comprising a pair of spacedthermo-responsive elements arranged to maintain a constant separationwhen the surrounding temperature changes, ry the temperature ofoneelement independent of the other element to contact it with the otherelement to close the circuit and means to vary the thermal characteflistic of one of termmed requiremen 2. A hermo-responsive devicecomprising a thermo-responsive element, the distortion of which isaffected by the temperature of the surrounding air, auxiliary means toeffeet the distortion of the element, means forming a part of theelement to adjust the degree to which the auxiliary means affects theelement and another thermo-responsive element affected in like eachother and rigidly the elements to meet a predemanner as the firstelement by temperature changes of the surrounding air, but not affectedby theauxil- 1ary means and adapted to make and'break' contact with thefirst thermo-responsive element under varying temperature conditions.

3. A thermo-responsive device comprising a pair of thermo-responsiveelements adapted to bedistorted to make and break contact with eachother said elements being constructed to respond alike to ambienttemperature changes irrespective of the speed of such changes tomaintain a constant relation with each other under changes in thetemperature of the surrounding air'and means for heating one of saidelements independently of the other to change the constant relationbetween the elements by affecting the amount of distortion of oneelement relative to the other.

4. A thermal current switch, comprising a pair of spaced bimetal stripsinsulated from mounted at one end of each strip, the opposite ends ofthe strips having cooperating contact points arranged to engage eachother caused to approach, said strips being arranged to be similarlyaffected by changes in ambient temperature to maintain substantiallyconstant spacing of said contacts in-' sofar as said strips are affectedby the temperature of the surrounding atmosphere, one of said stripshaving a slot therein extending fromthe fixed end thereof toward thefree end thereof, a rider mounted on said slotted strip and slidablymovable along said strip to bridge said slot at adjustable positionsalong said strip, an electric circuit having said slotted strip arrangedin series therein for supplying a current to said slotted strip to heatsaid strip independently of its cooperating strip, and a conductorconnected to said cooperating strip and arranged to be electricallyconnected with said slotted strip when said contacts are brought intoengage ment;

In testimony whereof I afix my signature.

HERBERT E. RUiPP when said ends are-

